The Uncaused Universe

From my studies in Cosmology I've come to the conclusion that, in line with the first law of thermodynamics, that the universe was not created, or caused if you like. I believe that before the universe arrived at it's present form of matter and energy, it existed timelessly in the form of vacuum fluctuation energy. I don't have a complete understanding of the subject, and any further insights, especially by experts, would be greatly welcomed.

I got my negentropy definition from Wikipedia, it's not just a lack of entropy.

Yes, people are thinking about what happened before the Big Bang. But without a theory of quantum gravity, they might never know for sure.

It's generally considered unphysical to have infinities around, like an infinite density at the Big Bang, and I guess people hope quantum gravity will take care of the infinities. When there are no longer infinities at the Big Bang, physics will extend to before the Big Bang. Also true in Roger Penrose's theory: since there is a rescaling of spacetime at the Big Bang, physics can evolve right through the Big Bang.

Stephen Hawking's "no boundary proposal" is a theory that does make predictions. Apparently his theory first predicted that the universe would recollapse; since it now appears the universe will expand in an accelerating way forever, he's revised the theory, at least according to what this person says.

I have come to think of the physical universe in terms of information. The universe started off with a finite supply of information, and a kind of "conservation of information" has required its expansion and Second Thermo at the macro level and Uncertainty Principle at the micro level.

Actually there's a definition of physical information which makes it (roughly) equivalent to entropy. When a "quantum measurement" event occurs, when there's a "throw of the dice", the information in the system increases.

Negentropy in this view is then -k ln(# states), the negative of entropy (rather obviously).

The merger of information theory with stat mech was all very smooth and easy; but when physicists tried extending that merger into other fields, a huge muddle developed involving many different ideas about the nature of information, as reflected in the Wikipedia article you link to. I don't cotton to those ideas; I prefer to stick to the first (successful) mating of information theory with stat mech. There's a lot of material here to cover; I could start a new topic to explain my thinking, but only if you're interested in pursuing it.

Two things that are interesting to me about this information/entropy business:

- apparently, the fundamental reason for the increase in entropy over time is quantum wavefunction collapse. That is the "toss of the dice" that generates new information.

- When computers do irreversible computations, they lose information and so there is a theoretical minimum to how much heat they can radiate! It's a direct connection between the abstract concept of information, and the physical reality of heat ...

the universe spreads in space, and today it still spreads. What makes it spread? The Big Bang! Now will it spread eternally or slows down and collapse? If it collapses, it becomes a Big Bang.

If the universe collapses again, it would not become another Big Bang, because the singularity at the end of the collapse would be very high in entropy, and the Big Bang was very low in entropy.

So that has been a big problem with cyclic-universe theories - they don't work because of the 2nd law of thermodynamics.

Roger Penrose's theory of "conformal cyclic cosmology", which he describes in Cycles ofTime, brings back the cyclic universe, in a new way: here, the accelerating expansion that we see in the universe today, is actually necessary for a new Big Bang! It looks now like the universe will never recollapse in the usual way - space won't start to contract again - BUT, Penrose suggests that the expanding universe will eventually lose any scale, so the size of the universe will be effectively 0, and that will be a new Big Bang.

The universe isn't actually spreading in space, it's space itself that is spreading, and at an accelerating rate.

Space is full of dark energy, which has the opposite effect from dark matter - it makes space expand. The dark matter clumps near galaxies - people think it exists because they can measure its gravitation, from effects on galaxies etc.

I don't know what cosmologists think about the origin of dark matter or dark energy.

The expansion of space only started accelerating about 5 billion years ago. That was when the influence of dark energy, which promotes expansion, started to be more important than the influence of matter, which promotes contraction. Matter was more important before then because the universe was smaller, so the average density of matter was higher.

Dark matter does seem to clump with ordinary matter, to some extent. One reason to believe dark matter exists is because galaxies spin faster than they should if they just had the ordinary matter that's estimated to be in them.

Agreed. The universe is much easier to hypothesize about if we begin with the premise that it always was and always will be, elastically speaking. Hence, big bangs (lower case) repeat throughout the giga-eons. Figuring out the time warp connectivity and the "cycles" of the universe is more interesting, and ignore any notion of there being an "origin" (or demise?). As a corollary, if the universe can be omni-temporal, is it also omni-spatial? If so, is there also space-warping?

According to Victor J. Stenger, one possible scenario of how our universe came to be (and it violates no known laws of physics), is through quantum tunneling from a universe on the other side of the t=0 barrier. Stenger says that the supposed arrow of time is illusory, especially on the quantum level, where effect precedes cause on a regular basis. According to Stenger's scenario, there may be another universe on the other side of the t=0 barrier, and that it's arrow of time is the reverse of our arrow of time. He hypothesizes that our universe tunneled from that universe in the direction of our arrow of time, while the universe on the other side of the t=0 barrier tunneled from our universe in an opposite arrow of time from ours. While he states it's only one possible scenario, he tells us it violates no known physical laws, and as long as we can come up with viable possibilities of how the universe can come to exist with no recourse to a god then there is no need to bring a god into the equations.

A parallel universe composed of anti-matter connected to our universe through black holes. I like it. (Didn't Star Trek do that one?) Yet, we haven't quite wrapped our minds around infinite time and how does atomic matter/energy exist without origin. I just accept these as the more plausible, and hypothesize from there.

I tend to take a dim view of the whole "parallel universe -- wormhole" thing. It's great fun, and makes for great stories, but I don't see much scientific merit in any of it. True, we can't rule such things out, but I think that there's a certain amount of wishful thinking involved when we talk about such things as real physical phenomena.

I don't seek to denigrate science fiction. Playing games with the laws of physics in order to make good stories makes for great storytelling. But I remind people, "It's just a story".